Effect of Yiqi Yangyin Decoction on suppressing tumor growth in mice bearing Lewis lung cancer via the Notch signal pathway and CD4^+CD25^+ regulatory T cells

Objective To investigate the dose-effect relationship for Yiqi Yangyin Decoction on suppressing tumor growth via Notch signal pathway and CD4⁺CD25⁺ regulatory T cells in mice bearing Lewis lung cancer. Methods Sixty inbred C57BL/6 mouse bearing Lewis lung cancer were randomly divided into four groups:model group(Group A),chemotherapy group(Group B),equivalent dose group(Group C),high dose group(Group D).The mice in Group A were only developed an animal model.The mice in Group B were induced by intraperitoneal injection of CTX according 15 mg/kg every week.The mice in Group C were treated with Yiqi Yangyin decoction of 0.435 ml/kg by intragastric gavage,and the mice in Group D were treated with Yiqi Yangyin decoction of 1.36 ml/kg by intragastric gavage.The change of tumor volume was recorded.Then all the rats were sacrificed and all tumor tissues were weighted.The Notch signal expression in tumor tissues was tested. Results ①Relative tumor volume(RTV) and relative suppressing-tumor rate:RTV of every group(except model group) was reduced.RTV of Group D was reduced mostly among the four groups.RTV of Group B was reduced more than that of Group C(P<0.05);the relative suppressing-tumor rate of Group D was highest in all four groups(P<0.05).The rate of Group B was higher than that of Group C(P<0.05).②The expression of Notch signal pathway and CD4⁺CD25⁺ Treg cell:the expression of Notch1 mRNA and CD4⁺CD25⁺ Treg in group C was higher than that in group B(P<0.05),but the expression in group D was lower than those in the group B and C(P<0.05);there was no significant difference in the expression of Notch3 mRNA between group B and group C(P>0.05),but the expression of Notch3 mRNA in group D was lower than those in the group B and C(P<0.05);the expression of Jagged1 mRNA and Hesl mRNA in group B,C and D were lower than that in group A(P<0.05);there was no significant difference in the expression of Jagged1 mRNA and Hesl mRNA between group B and group C(P>0.05),but the expression of Jagged1 mRNA and Hesl mRNA in group D was lower than those in the group B and C(P<0.05). Conclusion Yiqi Yangyin decoction can suppress the Lewis lung cancer cell,and the effect has dose-response relationship.The mechanism maybe associated to the expression regulation of Notch1 signal pathway and CD4⁺CD25⁺ Treg.